This invention relates to reciprocators and oscillators for spray guns and in particular to pneumatically powered reciprocators and oscillators for spray guns having minimal or negligible lag or return time.
Automatic industrial finishing requires equipment which can deposit uniform and consistant finishes while at the same time being economical and efficient with regard to operating costs and amount of finishing used.
A primary example of applications for automatic industrial finishing equipment is on power conveyor lines where unfinished articles continuously pass by the finishing equipment. In this one-pass situation, it is extremely critical that the finishing is deposited comprehensively and uniformly. Typical equipment utilize reciprocators (also called oscillators) which oscillate finishing guns adjacent to the unfinished products as they pass by so that the finish is deposited in an even manner.
Examples of the finishing substances which are applied by these devices are paints, electrostatic powders and liquids, liquid lacquers and enamels, adhesives, solvents, and cleaners. Additionally, sometimes foam injections are applied by this equipment. Many of these substances are volatile and therefore a critical requirement of finishing equipment in these applications is that they provide an explosion-proof atmosphere. This generally means that electric or gasoline powered reciprocators cannot be used because they present the danger of sparks and heat in a volatile atmosphere.
Many conventional reciprocators used today are hydraulically powered, using hydraulics to oscillate the finishing guns while maintaining an explosion-proof atmosphere. Hydraulic powered reciprocators are expensive, cumbersome and relatively difficult to maintain and repair because they require auxiliary equipment such as pumps and power units.
Attempts have been made to perfect a pneumatically powered reciprocator which would be less expensive, easier to transport, and more economical to operate and maintain. However, these attempts were not successful because a noticeable and detrimental lag or return time existed at opposite ends of the gun stroke which produced undesirable finishing results on the products. For example, the lag or hesitation at the end points would cause excessive amounts of finish to be deposited at those points on those products which thereby caused running or excessive thickness of finish.
Therefore, it is a principle object of this invention to provide a pneumatically powered reciprocator which solves the above mentioned problems in the art.
A further object of this invention is to provide a pneumatically powered reciprocator which eliminates or provides a negligible lag or return time at the end points of the reciprocator stroke.
A further object of this invention is to provide a pneumatically powered reciprocator which requires only one power source.
Another object of this invention is to provide a pneumatically powered reciprocator which is adjustable and operable to reciprocate finishing guns in any linear plane.
Another object of this invention is to provide a pneumatically powered reciprocator which utilizes pressurized air dump valves to accomplish elimination of lag.
A further object of this invention is to provide a pneumatically powered reciprocator which utilizes at least dual pressure to accomplish operability from one pressurized air souce.
A further object of this invention is to provide a pneumatically powered reciprocator which is adjustable in stroke length and oscillation speed and has highly accurate speed matching between direction of travel of the spray guns and has precise travel speed.
A further object of this invention is to provide a pneumatically powered reciprocator which is simple in design and operation.
Another object of this invention is to provide a pneumatically powered reciprocator which is easy to maintain and repair.
A further object of this invention is to provide a pneumatically powered reciprocator which is durable, economical, efficient, and easily maneuverable and moveable.
Additional objects, features, and advantages of the invention will become apparent with reference to the accompanying specification and drawings.